Authors:

Rohan Patil(North Carolina State Univ)

Jiri Srogl(North Carolina State Univ)

Douglas Kiserow(U.S. Army Research Office)

Jan Genzer(North Carolina State Univ)

Polymer brush degrafting refers to the removal of grafted polymer chains
from the substrate without harming the polymer chemical structure. We grow
poly(methyl methacrylate) (PMMA) brushes on flat silicon substrates using
atom transfer radical polymerization (ATRP) and remove them from the surface
by exposing the samples to tetrabutyl ammonium fluoride. We then analyze the
polymer molecular weight of degrafted PMMA chains by size exclusion
chromatography. The kinetics of PMMA brush degrafting exhibits double
exponential behavior suggesting a transition from `brush' to `mushroom'
regime. The dry brush thickness increases initially with increasing
polymerization time. At longer reaction times, the thickness starts to
plateau due to loss in the living nature of ATRP. We examine the
relationship between the brush dry thickness and molecular weight and show
that grafting density of the PMMA brush does not remain constant over the
course of polymerization but reduces with time.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.P1.232